The present invention generally pertains to injection molding of elongated articles, such as cable ties, and is particularly directed to methods for reducing the cycle time for injection molding of such elongated articles.
A cable tie is an adjustable strap for bundling together articles such as cables or the like. Cable ties are also known as cable straps, cable clamps, cable clips, bundling ties, bundling straps, bundling clips, bundle ties, bundling belts, wire ties, ring clamps, adjustable clamps, harnessing devices, strap seals, binding straps, and ties. A typical cable tie includes an elongated strap with an adjacent locking head at one end of the strap, a tip at the opposite end of the strap and ratchet teeth on one side of the strap. The locking head defines an opening for allowing the tip end of the strap to be pulled through the opening and thereby form a closed loop around a bundle of articles. The locking head typically further includes a pawl having teeth with surfaces for engaging the ratchet teeth to lock the strap in the locking head after the tip end of the strap has been pulled through said opening. Examples of cable ties are described in U.S. Pat. Nos. 3,739,429, 3,924,299, 3,965,538, 4,473,524 and 4,573,242.
Cable ties are manufactured economically by a cyclic injection molding method, in which molten plastic material is injected into a mold cavity defining the cable tie and then allowed to solidify within the mold cavity. The mold parts defining the mold cavity are then separated and the cable tie is ejected, first from the mold parts and then from the space between the mold parts. A preferred material for cable ties is nylon.